Wind tunnel models typically use movable control surfaces to efficiently simulate various control aspects of a vehicle being modeled. Unmotorized surfaces are often used due to their simplicity and ability to operate at extreme temperatures. However, such surfaces must be positioned by hand requiring interruption of testing to position the surfaces at desired control angles. Thus, existing solutions require removal and/or isolation of the model from the wind tunnel environment to make configuration changes.
Models are typically of reduced scale, and therefore, full size actuators which would be employed in actual vehicles are not readily adaptable for use. Various actuation systems have been employed in wind tunnel models including electromechanical actuators. However, electromechanical actuation is relatively bulky because of low power densities and the need for complex electric motor/gear assemblies. As such, the amount of space required in the supporting structure (for example, in a vertical tail of an aircraft) may limit the amount of instrumentation, such as pressure sensors, that can be installed in the model and may reduce structural strength which tends to limit their use to lower pressure tunnels having lower loads. Subscale models in lower pressure wind tunnels do not match the aerodynamic characteristics of a full scale aircraft as well, which limits their fidelity as design tools for testing aircraft configurations.
It is therefore desirable to provide an actuation system for use in models tested in harsh wind tunnel environments, or other temperature or load restricted applications, to improve wind tunnel test efficiency by reducing the number of times the wind tunnel is opened to complete model changes, while providing an actuator with sufficient force capability for cryogenic or higher pressure wind tunnels.